Left atrial thrombi in mitral valve disease

Increased platelet activation and endothelial dysfunction in patients with atrial fibrillation immediately following percutaneous balloon mitral valvuloplasty

BACKGROUND

Immediately following percutaneous balloon mitral valvuloplasty (PBMVP), patients have a 3% risk of systemic thromboembolism.

HYPOTHESIS

We hypothesized that this may in part be due to an increase in hypercoagulability (as indicated by abnormal coagulation, platelet activation, and endothelial dysfunction) in such patients.

METHODS

We measured indices of platelet activation [soluble P-selectin (sPsel), ELISA], endothelial dysfunction [von Willebrand factor (vWf), ELISA], and coagulation (fibrinogen, modified Clauss) in 16 patients (15 women, mean age 59 +/- 10 years) with chronic atrial fibrillation admitted for PBMVP, and 16 healthy age- and gender-matched controls. Blood samples were obtained as follows: (1) peripheral venous samples prior to PBMVP, immediately following PBMVP, and 24 h after PBMVP; and (2) arterial samples prior to and immediately following PBMVP.

RESULTS

Patients with mitral stenosis and chronic atrial fibrillation demonstrated significantly higher mean levels of vWf [148 (SD 24) vs. 102 (SD 37); t-test, p < 0.001] and plasma fibrinogen [4.2 (SD 0.8) vs. 3.3 (SD 0.8); p = 0.003] at baseline than matched healthy controls. There was a nonsignificant trend toward lower median sP-sel levels in patients with mitral stenosis [64 (inter quartile range 47-91) vs. 109 (46-128); Mann-Whitney test, p = 0.08]. Following PBMVP, there was a significant increase in venous sP-sel levels immediately post procedure (paired Wilcoxon test, p = 0.03) and at 24 h afterward (p = 0.01). Arterial s-Psel levels correspondingly increased immediately post procedure (p = 0.008). There was a significant increase in mean venous (at 24 h) but not arterial vWf levels post PBMVP. There were no significant changes in mean venous or arterial plasma fibrinogen levels following PBMVP.

CONCLUSION

Patients with mitral stenosis and chronic atrial fibrillation have increased plasma levels of vWf and fibrinogen levels compared with healthy controls, suggesting increased endothelial dysfunction and coagulation at baseline in these patients. The increased levels of sP-sel immediately post procedure and at 24 h, in association with increased vWf levels at 24 h after PBMVP, are in keeping with an increase in platelet activation and endothelial dysfunction following PBMVP. These changes may contribute to the increased risk of thromboembolism following PBMVP and suggest the need for adequate antithrombotic therapy following PBMVP.

Predictors of left atrial thrombus and spontaneous echo contrast in rheumatic valve disease before and after mitral valve replacement

In this study we aimed to analyze, with reference to mitral regurgitation (MR), the incidence and predictors of left atrial (LA) thrombus and spontaneous echo contrast in patients with rheumatic valve disease before and after mitral valve replacement. The incidence of LA thrombus is known to be less in patients with MR. The impact of mitral valve replacement on this beneficial effect has not been studied in detail. The study included 169 consecutive patients (59 men and 110 women, average age 40 +/- 13 years) with rheumatic mitral valve disease who underwent transesophageal echocardiographic examination 1 to 3 days before and within 7 days (mean 4.0 +/- 1.3) after mitral valve replacement using mechanical prostheses in a single institution. The preoperative incidence of echocardiographic LA spontaneous echo contrast (SEC) was 1.1%, 30%, and 54%, and the incidence of thrombus was 1.1%, 13%, and 17% in the groups with MR, combined mitral stenosis + MR, and isolated mitral stenosis, respectively. In the MR group, SEC and thrombus incidence increased significantly after surgery. The independent predictors for postoperative thrombus development were atrial fibrillation, postoperative SEC, and preoperative thrombus. Thrombus recurred after surgery in 64% of 14 patients who had surgical thrombectomy. The presence of postoperative MR was associated with decreased risk of postoperative SEC and thrombus development. The interaction between MR and SEC and thrombus both before and after surgery provides further support for the protective effect of MR against LA thrombus formation.

Closed mitral valvotomy: early results and long-term follow-up of 3724 consecutive patients

Between 1956 and 1980 closed mitral valvotomies were performed in 3724 consecutive patients (male:female ratio 1.1:1) with mitral stenoses. Their ages ranged from 6 to 69 years, with a mean (SD) of 27.3 (9.3). Mitral stenosis in the younger age group is a unique condition and a great majority of these patients rapidly develop significant pulmonary hypertension and congestive cardiac failure. In this study a large number of subjects belonged to functional class IV (41.5%). Hospital mortality was 1.5% over the last 5 years. After valvotomy, 11 patients (0.3%) developed severe mitral regurgitation that made valve replacement necessary in the immediate postoperative period. Early postoperative embolism occurred in 0.4% of those who were in atrial fibrillation and had preoperative anticoagulation whereas it occurred in 0.95% of those in sinus rhythm who had no anticoagulation. Late postoperative embolism occurred at a rate of 0.3 to 1.6 per 1000 patients per year over a 20 year period. Rheumatic reactivity occurred at a rate of 1.3 to 2.2 per 1000 patients per year during the same period. Rate of occurrence of restenosis varied from 4.2 to 11.4 per 1000 patients per year between the fifth and fifteenth year of follow-up. Closed transventricular revalvotomy for restenosis was accomplished in 130 subjects with a 6.7% mortality. Excellent symptomatic improvement was evident in 86% of long-term survivors at the end of 15 years. Actuarial survival was 95%, 93.1%, 89.5%, and 84.2% at 6, 12, 18, and 24 years, respectively, after closed mitral valvotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

A safe technique for removal of massive left atrial thrombus

Open mitral operation in patients with massive left atrial thrombus still carries a high mortality due to intraoperative embolism. To prevent this danger, we have standardized a surgical technique that includes careful handling of the heart and use of suction, blockage of the mitral orifice, and excision of subendocardial thrombus. Our total experience with massive left atrial thrombosis comprises 30 patients. Seven out of 8 patients operated on before our present technique was used died in the hospital of irreversible cerebral damage. The other 22 patients underwent operation with this technique, and the thrombus was removed without mortality or morbidity.

Massive left atrial thrombus complicating mitral stenosis with atrial fibrillation: results of surgical treatment

Thirty-five patients with massive atrial thrombus complicating mitral stenosis and atrial fibrillation were treated surgically. The mean age in this series is lower than that reported in the West. Furthermore, the incidence of preoperative embolic manifestations has been less frequent in our experience. We believe it is desirable to document the presence of a thrombus by selective left atrial cineangiography. Surgical treatment was accomplished with an acceptable mortality. The vital role played by the use of low-molecular-weight dextran and early anticoagulation in decreasing the incidence of postoperative cerebral embolism is emphasized. Follow-up data in the survivors has shown excellent functional status with no late embolic phenomena in any subject.